Myocardial ischemia is a cardiac function disorder caused by insufficient blood flow to the muscle tissue of the heart, most commonly due to narrowing of the coronary arteries. Conventional techniques monitor changes in an electrocardiogram (e.g., a surface electrocardiogram (ECG), or an internal electrogram (EGM) obtained by leads implanted in the heart) to detect myocardial ischemia. In particular, myocardial ischemia is typically diagnosed based on abnormalities detected in the ST segment of an electrocardiogram.
While monitoring cardiac electrical activity using an electrocardiogram is one technique for diagnosing myocardial ischemia, it is expected that cardiac pressure sensors of implantable cardiac devices will be used more frequently to monitor cardiac functionality. What is needed, therefore, are systems and methods for using an implantable cardiac device to monitor both electrical and mechanical conditions of the heart for reliable ischemia detection.